Jaylen Brown nailed 27 points, while Jayson Tatum added a further 26 as a rock solid Boston defence kept Steph Curry and the Warriors at bay for most of the game to put the Celtics just two games away from a 18th NBA title.
Marcus Smart added 24 as Boston fought off a Warriors third quarter fightback to drag the game back in their favour and comfortably ease through the final period.
There could be further concerns for Warriors star man Curry who left the game late in the fourth quarter with a leg injury, having scored a game-high 31 points. Klay Thompson (25 points) and Andrew Wiggins (18) also chipped in for Golden State but it wasn't enough.
Boston stormed into an 18 point lead during the first quarter with Brown scoring 17 of his 27 points. They dominated the rest of the half and went into the break with a 12-point lead at 56-68.
Warriors dragged themselves back into the game in the third quarter, with Steph Curry leading the charge as they briefly took a 83-82 lead. But the Celtics absorbed the pressure and took control in the fourth to see out the victory.
Curry tried to shrug off the his late injury and doesn't feel like he'll miss Game 4.
"I'll be alright. I got caught - obviously in some pain, but I'll be alright," said Curry. " "Same thing I did against Boston in the regular season, but not as bad.
"See how it feels (Thursday) and get ready for Friday. ... Don't feel like I'll miss a game. Take advantage of these next 48 hours to get ready."
"We need him if we want to win this thing," said Warriors shooting guard Klay Thompson. "And I know Steph will do everything he can in his power to play. I'm really hoping he's okay because he is our identity and without him, it will be very difficult."
Warriors coach Steve Kerr refused to be drawn on Curry's injury saying: "The injury didn't force him out of the game… We'll know more tomorrow."
Game 4 is also in Boston on Friday night at 21:00 (EST)